Simple Crypto module for encrypting and decrypting strings using a secret token stored in application config. Useful for creating email tokens which contain some data about the user for retrieval.

crypto.rb

module Crypto
  def encrypt(string)
    Base64.encode64(aes(Application.config.secret_token, string)).gsub /\s/, ''
  end

  def decrypt(string)
    aes_decrypt(Application.config.secret_token, Base64.decode64(string.gsub(" ","+")))
  end

  def aes(key,string)
    cipher = OpenSSL::Cipher::Cipher.new("aes-256-cbc")
    cipher.encrypt
    cipher.key = Digest::SHA256.digest(key)
    cipher.iv = initialization_vector = cipher.random_iv
    cipher_text = cipher.update(string)
    cipher_text << cipher.final
    return initialization_vector + cipher_text
  end

  def aes_decrypt(key, encrypted)
    cipher = OpenSSL::Cipher::Cipher.new("aes-256-cbc")
    cipher.decrypt
    cipher.key = Digest::SHA256.digest(key)
    cipher.iv = encrypted.slice!(0,16)
    d = cipher.update(encrypted)
    d << cipher.final
  rescue
    return false
  end
end